Study Of New Post Treatment Process Of Glyphosate Reaction Liquid

With the continuous development of economy, people pay more and more attention to their life quality as well as environment and ecology protection and the state has also promulgated a series of laws and policies on environment protection and glyphosate(PMG) production. Currently, IDA is a world wide most used method of synthesizing PMG. How to separate PMG from reaction liquid efficiently is still difficult for the PMG branch. Therefore, the research of efficient separation of PMG makes great environmental and economical sense. In this paper, in view of the aftertreatment technology of reaction liquid of PMG which salt-free and with salt,respectively putting forward the low pressure crystallization separation of PMG and the new technology of mother liquor recycling that low evaporating crystallization PMG and salting-out by-product ammonium chloride at the same time. This reduces the waste water from the source and has good environmental and economic benefits.First, in view of the PMG salt-free process of wastewater concentrating, the stability of PMG and N-(Phosphonomethyl)iminodiacetic acid(PMIDA) was explored and the temperature and concentration of formaldehyde on the effect of PMG and PMIDA content was studied. The experimental results show that the temperature below 100 ℃, PMG and PMIDA is stable; High temperature and concentration of formaldehyde can make the transformation of the adverse event of PMG fast; When formaldehyde concentrations between 1% ~ 3% and the temperature is below 80 ℃, two hour before reaction, the variation in content of PMG is small;Within the temperature of 100℃ and formaldehyde concentration below 5%, PMIDA is not produce adverse event and its content is not affected.In addition,the effect of the enrichment degree, concentration time, PMIDA concentration, crystallization time and initial concentration of formaldehyde on yield and content of PMG was explored. The experimental results show that when the degree of enrichment is greater than 1:1. 9, With the increase of concentration degree,the purity of PMG to crystallize is smaller; concentration time is almost no influence of PMG purity; When the mass fraction of PMIDA is more than 0.5%, the purity of PMG to crystallize is not affected, but its crystal yield decreases; Crystallization time has no impact on the purity of PMG, but with extension of the crystallization time, its yield increase with steps; When the initial concentration of formaldehyde is 1%, bothof the purity and yield of PMG is no impact. When at the formaldehyde concentration is greater than 3% and higher temperature, the crystallization of PMG purity and yield are lower; Under high temperature and concentration of formaldehyde, methylation reaction of PMG and formaldehyde is speeding up; When the degree of enrichment of1:1. 9, the mass fraction of PMIDA under 0.5%, formaldehyde concentration under3%, concentrated time for 1 hour, crystallization time for 3 h, the quality score of PMG powder is above 96% and its yield can reach about 75%; Concentrate after filtration cycle for reaction can reduce the generation of wastewater.Secondly, in view of the PMG salt process of wastewater treatment, water balance method is used to determine the solubility of ammonium chloride in the three system of hydrogen chloride- water- ammonium chloride. Based on the mechanism of acid system of weak acid and the same ion effect, putting forward the new technology of mother liquor circulation of aftertreatment that the reaction liquid salting-out by-product ammonium chloride. The experimental results show that the greater the concentration of hydrogen chloride, ammonium chloride solubility is smaller; When the mass fraction of HCl is 5% ~ 10%, mass fraction can be obtained in more than 95% of by-product NH4Cl; The mass fraction and yield of PMG powder are all above 95%; Mother liquor can circulate 8 times and this new technology can reduce the waste water generation.